Centrifugal compressor



MOTOR 000 00m 000 @om vom aOma 00a H. A. JOHNSON CENTRIFUGAL COMPRES S OR original Filenec. 13, 1944 Howard A. Johnson,

His Attorney.

Patented Feb. 10, 1948 Howard A. Johnson, Melrose, Maas., assigner to General Electric Company, a corporation of New Yori?.

original applicaties Deeembelis, 1944, serial Ne. 567,993. Divided and this application May 1, 1946, Serial No. 668,818

The present invention relates to aircraft power-plants including a turbosupercharger for air to a combustion chamber or gas generator for producing gases to operate such aircraft by jet propulsion.

` This application is a division of my earlier application, Serial No. 567,993, tiled December 13, 1944.

An object of my invention is to provide an improved aircraft powerplant for propelling an aircraft by propeller and Jet propulsion. Another object of my invention is to provide an improved turbosupercharger arrangement for iurnishing compressed air to various consumers on an aircraft. A further object is to provide an improved centrifugal compressor especially adapted for use in gas turbine powerplants.

For a consideration of other objects and of what I consider novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.' f

In the drawing, Fig. 1 illustrates an aircraft powerplant according to my invention; and Fig. is an enlarged view of a part of Fig. 1.

The powerplant shown comprises a coinbustion engine I arranged to drive a propeller K@for propelling the aircraft. The engine has an inlet manifold connected to a supply conduit 9 for compressed air in series with a carburetor l and an exhaust manifold connected to an exhaust conduit 5. 'I'he 'engine I is supercharged by means of a turbosupercharger which has an exhaust gas operated turbine B connected to the exhaust conduit and normally operated by exhaust gases of the engine. The turbine drives a compressor 'I for supplying compressed air to the inlet conduit 3 of the engine I.

, The arrangement so `far described is known 3 Claims. (Cl. 23d-114) buckets 9 attached to its rim and integrally formed with an overhung portion of a shaft I9 supported on a casing II bymeans of bearings I2. Operating gases are conducted to the bucket wheel 9 by means including a nozzle box I9 concentricaliy spaced from the right-hand end of the casing II and having an annular row of nozzle partitions Il for directing gases toward the buckets 9. The box I9 has a ilanged inlet I5 connected to the aforementioned exhaust conduit 9 ofthe engine I.

The centrifugal compressor 'I comprises a caslng having two halves I9, I1 forming an impeller chamber with two axial inlets or eyes I 8 and I9 respectively. A dual impeller is disposed in the impeller chamber and has a disk 2li secured to the shaft I9 and provided with circumferentially spaced blades 2i and 22 on opposite sides. The impeller blades 2i form passages for receiving air or like medium through the inlet I9, and the impeller blades n form passages for receiving air to be compressed through the inlet I9. The leithand end ot the shaft Ill is additionally supported by a. bearing 29 having a housing held on guide vanes 24 in the inlet I9 oi' the casing into pressure energy. Thel diifuser comprises axially spaced walls 25 and 29 secured to the casing halves I9 and I1 respectively and'fcircumferentially spaced vanes 21 forming diffuser and typical of turbosupercharged internal comto my invention includes means with a special compressor arrangement whereby either the jet propelling device or the propeller propelling combustion engine may be operated alone. The turbine, as shown more in detail in Fig. 2, comprises a bucket wheel 8 having a disk with a row of passages with the/walls 25. 2B. During operation, a part of the air discharged from the diffuser is passed into a scroll 28 which hasr a iianged outlet 29 connected to the aforementioned conduit 9 to furnish compressed air for operating the combustion engine I. Another part of the compressed air discharged from the diifuser passes into flanged outlets or chambers which are connected to gas generators or combustion chambers, as will be described more fully hereafter.

According to my invention means are provided for smoothly detlecting compressed air into the scroll 29 and into the 'outlets Inland also for varying the relative amounts of air or the ratio of ow conducted to the scroll 28 and into lmediate position as shown in full lines in the drawing to deflect part of the compressed air or medium into the scroll and another part into 3 the outlets 3l. The ringmember Il is axially guidedontheouterwallofthecompressorand may be moved and positioned axially by means including a motor $4 connected to a positioning an axillly adjustable wall common to separate chambers on opposite sides of the compressor. When moved into its left-hand end position,

as indicated in dotted lines, the ring member II disconnects completely the scroll' from the ditluser so that all compressed air isdenected through the outlets Iii. A plurality of curved, essentially conical concentric guide channels It member Il. Broadly, the defIector--Siconstitutee are located near the inlet Il of the compressor properly to d irect` air to be compressed toward the impeller blades 22. The compressor casing is supported on the casing Il by means of a Each outlet 30 of the compressor is connected to a gas generator or combustion chamber 30 having an outer cylindrical'wall 40 sealed to the end of a conduit 4I by a suitable packing 42. The conduit 4| is anged to an outlet 30. An inner, perforated, cylindrical wall 43 is disposed within the wall 40 and closed at its left-hand end by a cup-shaped bottom 44. The bottom 44 and the perforated cylinder 3 constitute the combustion chamber' proper. Fuel is supplied thereto by means of a nozzle 45 held in the bottom 44 and connected to a fuel manifold or ring 48. Air is supplied to the combustion chamber from the outlets 30 through the perforations of the cylinderv 43. The combustion gases formed in the combustion chambers are supplied to a jet-forming device 41 which latter has an outer'wall 48 and an inner wall 49 forming an annular channel l0 between them for receiving gases from the combustion chambers. The inner wall 40 is sealed to the rim of the bucket wheel by a suitable packing 5 I. The right-hand end of the outer wall 48 has an extension or tail cone 52. The exhaust gases of the turbine are also discharged through the annular channel 50, and to reduce interference between the operation of the gas turbine and combustion chamber an intermediate wall or ring 53 is provided in the inlet part of the annular channel 5I! and secured at its lefthand end to the nozzle box Il to form with the inner Wall 49 a channel 5 4. A plurality of guide vanes 55 are located in the channel 54 tcrecelve exhaust fluid from the turbine wheel and to turn such fluid in rearward direction.

The various combustion chambers are supported` on the nozzle box I3 and the casing I I by means including a ring or partition 5B secured at its inner end to a wall or partition 51 held on lugs Sil on the casing II. The partition or support Il and the partition 5B are arranged to reduceheat transfer from the combustion chambers and the nozzle box of theturbine to the casing II. The inner wall of the nozzle box is sealed to the bucket wheel by a suitable packing Il to reduce leakage of gases from the nozzle box Y lli and 2l in casing il andalsotosupply fueltothe fuel ring 4I.

During normaly operation, combustion gases from the engine I are supplied to the gas turbine acting as an operating medium for the latter. The double impeller of the compressor takes In air through the inlets I8, I! and forces it through the diffuser 25, 26, 21. Part of this air is passed through the scroll 28 to the engine I .to super- "charg the latter, and another part of the air is supplied through the outlets l0 to the combustion chambers to maintain combustion therein. The combustion gases from said chambers are discharged into a. jet-producing device 41 which also receives exhaust gases from the turbine.

The jet-propelling arrangement may be operated during high load requirement, such as during take offs, and at high speed. The ratio of airflow to the enginel and to the combustion chambers may readily varied by positioning of the ring member 3| of the compressor. Upon interruption of the oil supply to 4fthe manifold 4l, the air supplied to the outlet, 3| will be bypassed through the combustion chambers to the annular channel 50 where it mixes with the engine exhaust gases and causes further burning and expansion thereof to increase the jet power. In certain instances, such as upon failure of the combustion engine I, it may b'e desirable to operate the aircraft solely by et propulsion. This may be readily accomplished Iy my an'ange' ment which includes means for conducting operating gases from the combustion chambers to the gas turbine 6 upon failure of the combustion engine I which latter constitutes the normal source of supply for the turbine.l To this end some of the channels between the combustion chambers and the annular channel SII are connected to the nozzle box Il by means including valves 64 having operating arms 6l. In addition, the flanged inlet I5 is provided with a valve B6. During normal engine operation the valve "is open to admit exhaust gases from the engine into the nozzle box I3. The valves i4 controlling communication between the combustion chambers and the nozzle box are normally closed, as indicated in full lines in Fig. 2. Upon failure of the engine I for driving the propeller 2, the valve 66 is closed to disconnect the nozzle box I3 from the engine I and the valve or valves 84 are opened. AWhen fully opened, al1 of the gases produced by the combustion chambers are passed into the nozzle box and when partially opened..

as indicated in dotted lines', part of the gases are conducted to the nozzle box and another part to the channel 50.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A centrifugal compressor comprising an impeller, a diffuser surrounding the impeller, a discharge scroll located substantially on one side of the diffuser for receiving air from'the diffuser. other means located on the other side of the diffuser and also connected to receive air from the diffuser, deilecting means comprising an axially movable ring concentrically surrounding the diffuser for controlling the ratio of flow to the discharge scroll and said other means. and means external of the compressor for positioning said rings.

2. A centrifugal compressor comprising an impeller, a diifuser surrounding the impeller, means formin-g separate axially spaced discharge e chambers connected to the diffuser at opposite sides thereof. said chambers having an annular disk disposed in the casina, a diuser surrounding the impeller, a discharge scroll located substantially on one side of the diiluser for receiving part 1 oi' the uid ow therethrough. and means forming a plurality of circumterentially spaced outlets on the other side of the diffuser, a deector concentrically surroundinz the diffuser for directin! llld into the dlsch'le s011111 md Bald outlets 15 2,205,902

assunse x I respectively, and means icr axially positioninl the deector to vary the ratio ot ilow into the scroll and the outlets.

HOWARD A. JOHNSON.

ABEFERENCI'JS CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,281,807 Greenawalt Apr. 9, 1918 1,550,710 Schmidt Aus. 25, 1925 Mellahan f.. June 25, 1940 

